Catalytic conversion of hydrocarbons



Aug. 6, 1940. R. PizEl. er A1.

I CATALYTIC CONVERSION OF HYDROCARBONS Filed Aug. l2, 1939 .NETH- `our co-pending application Serial No. 245,840,v

remitan Aug'. e,

IIJNI-TED- fsTATE-s :area51 PATENT OFFICE;

oA'rALmo coNvEnsloN or maocAanoNs Robert Pysel and Clarence G. Gerhold, Chicago, Ill., assignors to Universal 0i! Products Company, Chicago, lll., a corporation of Delaware Application' aufm iz, 193s, serial No. 289,122 1 claim. (ol. las-sz) This applicationr'is a continuation-impart of tiled December l5, 1938.

l'I'he invention relates yto an improved process and apparatus for conducting catalytic reactions yof the type in which the activity of the, catalyst `is reduced by the deposition of deleterious materials thereon as the operation progresses and wherein the catalyst is periodically reactivated by .contacting the same with a reactivating medium which serves to remove or destroy the deposited deleterious materials" without-injuring the catalyst. a

. The features of Athe invention are"applicable to any catalytic reaction of the general type above mentioned, wherein the stream of reactants to be catalytically treated or convertedand a stream oi' the reactivating medium 'are each separately heated prior to their contactwith the catalyst and wherein said catalytic treatment or conversion of the reactants and reactivation of the catalyst are accomplished simultaneously in separate reactors which are alternated with respect to the reactivating and processing steps. In most proc- Yesses of this general type, catalytic treatment oi' the reactants is endothermic and reactivation-oi' lthe catalyst is'exothermic, although in some instances both ,reactions'are exothermic. Many of the well known processes for the catalytic conmatization,

` advantages, is directed` to a process of theiirst mentioned group, above mentioned, and an apparatus in which to conduct the process, wherein the stream of hydrocarbons to be converted is first heated to a temperature at which the desired conversion reaction will occur upon contact of the y heated reactants with the catalyst and then passed through one of a plurality of alternately operated reactors, containing the catalytic material and wherein said catalytic corversionis accomplished, while previously used catalyst which has been reduced in activity by the deposition of heavy carbonaceous materials formed during conversion of the reactants is simultaneously reactivated in another reactor oi' the group by separately heatingy a stream o! loxygen-containing gases and passing the hot oxygen-con- 5 taining gases in contactwith the catalyst.

The inventive features ofthe process and apparatus herein disclosed reside inthe provision Lof primary and secondary heating zones for accomplishing heating uf me stream of nydrocarl0 bon reactants and heating of the stream oi' 'reactivatingl gases prior to their contact with the catalyst, the primary heating zone being continuously employed during the operation for heating the stream of hydrocarbon reactants to a relaing zone comprising separate, alternately operated heating coils through one of whichv the'mildly heated hydrocarbons from the primary heating tively mild temperature and the secondary heatzone are passed and brought to the desiredconversion temperature, while the oxygen-containing reactivating gases, which preferably have also been preheated, but not to the same extent as the hydrocarbons, are simultaneously passed through another of said secondary heating coils, with provision forv periodically diverting the. ilow of reactivating gases to the :flrstmentionedr heatili! coil and diverting the flow of mildly heated hydrocarbons from the primary heating zone to the second mentionedheating coil.

`'iVitl-i the arrangement-above outlined, no cokf ing diiilculties are encountered in the relatively high temperaturesecondary heating zone,since any small amount of coke or heavy carbonaceous material deposited withineach coil, while it is em- 35 ployed to heat the hydrocarbon reactants, is burned therefrom at relatively frequent periodical intervals by passing therethrough the stream .of oxygen-containing reactivating gases being supplied to the catalyticreactonin which reactiva- 40 tion is taking place. A further advantage results y from the position of the switching valve or valves by means of which the stream of hydrocarbon reactants is periodically diverted from its path ot flow through the reactor in which catalytic con- 45 version thereof has been taking place to the reactor containing freshly reactivated catalyst, while the stream of reactivating gases is diverted from its path ofiiowto the reactor-wherein'reactivation has been completed to the reactor con- A50 taining catalyst which requires reactivation.

-With the system provided by the invention. the

switching valve or4 valves are located in a relatively cool zone along the path of iiow of the reactants and reactivatinggases.v This permits the` 6l oxygen (usually in the form of air).

tion, designed for lower temperature service and less severe operating conditions in general, as compared with a system in which the switching valves are located'in a relatively hot zon'e' immediately ahead of the catalytic reactors, as-is conventional practice.

In the accompanying drawing Fig. 1 is a flow diagram illustrating the process now. Figs. 2 to 5 inclusive diagrammatic'ally illustrate the switching valves 4 and I8 of Fig. 1 and show the respective paths of* flow therethrough for the reactants and reactivating gases. Although the drawing Vshows the apparatus in diagrammatic forml the apparatus features of the invention are believed to reside in the general arrangement of the es.

sential elementsY of the system, rather than in their specific form and the drawing adequately illustrates this concept of the invention.

` Referring to the drawing, the stream of hydrocarbon reactants to be converted is supplied through line I to primary heating zone 2 which may be of any desired conventional form capable of heating the reactants to the desired relatively mild temperature. The mildly\ heated reactants are directed from zone 2 through line `Il to a stream-directing mechanism or switching valve 4 wherethrough it is directed, as` desired, either via line 5 to a secondary relatively high temperature heating zone 6 or via line 'I to a substantially identical or similar heating zone 8. 'I'he stream-directing mechanism or switching valve serves as a means of periodically alternat.

ing the path of flow of the mildlyl heated reactants with respect to zones 6 and 8 and also alternating the path of flow of a stream of reactivating gases with respect to zones Ii and 8. 'I'he reactivating gases which may comprise,'for example, combustion gases, steam or other material which does not adversely effect the catalyst employed containing controlled amounts of The reactivating gas stream is supplied to valve 4 through line '8 and is directed by valve 4 to secondary heating zone 8 when the stream of mildly heated reactants issupplied from zone 2 to zone 6 and after adjusting valve 4, the\gas stream is directed to zone 6 while the reactants are supplied to zone 8. The reactivating gases may also bepartially heated, prior to their introduction into coil I8 or coil II, as the case may be, this being accomplished, for example, by compression, heat exchange or in any other well known manner not shown.

The stream-directingmechanism may comprise a conventional manifold arrangement having a plurality of valves of any conventional construction and design capable of functioning under the condition of service to which they are'subjected or it may comprise a fourway valve of the reciprocating plunger or rotary plug type, such as illustrated diagrammatically in Figs. 2 and 3.

With the valve adjusted as illustrated in Fig. 2, the mildly heated reactants from zone 2 and line 3 are directed through line 5 to secondary heating zone 6, while the reactivating gases from line 9 are directed through line 1 to secondary heating zone 8.' With the stream-directing mechanism of valve 4 shifted so that the flow therethrough is as illustrated` in Fig. 3, the mildly heated reactants from zone 2 and line 3 are directed through line I to secondary heating zone 8, while the reactivating gases from line 9 are directed through line 5 to secondary heating zone 6.

2,210,257 use of switching valves kkof less costly construc- 'I'he secondary heating zones 8 and 8 preferably contain simiiar or substantially identical heating coils or other suitable iluid conduits II and II, respectively. Heating zones 6 and 8 may comprise separate structures independently fired or otherwise independently supplied .with the required heat or the uid conduits I8 and II may be so disposed in a single or in separate heating compartments of a furnace structure or the like to receive heat either substantially uniformly or, when required, at different, independently controlled rates. It is also entirely within the scope of the invention to dispose zones 8 and 8 in the same or separate relatively high temperature compartments of the same furnace structure in which zone 2 is disposed.

The streams of reactants and reactivating gases passing through zones 6 and 8, respectively, or zones 8 and 8, respectively, are separately heated to desired temperatures. 'I'he temperature at which the reactants are heated 'is such that the desired conversion thereof will occur upon their subsequent contact with the active catalyst employed and the temperature to which the oxygencontaining reactivating gases are heated is such that combustion of the carbonaceous material deposited on the catalyst, which requires reactivation, will be initiated upon their contact therewith.

Lines I2 and I3 connect uid conduits4 I8and II, respectively, with the respective catalytic reaction zones I4 and I5 which are alternately operated as zones of catalytic conversion and reactivation, the reactivated catalyst disposed in zone I4 being employed for promoting the desired conversion reaction of the heated reactants from fluid' conduit I8 when reactants from zone 2 are supplied to the latter, whileanysmall amount of carbonaceous material. deposited in the fluid conduit Il and on the catalyst disposed in zone `I5 is burned therefrom by contact with the stream of hot reactivating gases. Similar carbonaceous material deposited in the fluid conduit I8 and on the catalyst disposed in zone I4 is burned therefrom, while the reactants from zone 2 are heated to the desired higher temperature in fluid conduit II and catalytically converted in zone I5. The materials discharged from zones I4 and I5 are directed through the respective lines i6 and Il to the stream-directing mechanism or switching valve I8, whe're'from the spent reactivating gases are discharged through line I8 preferably to suitable heat recovery. scrubbing and circulating equipment, not illustrated, wherefrom they may be returned together with added air or oxygen to line 9 for further use, while the conversion products are discharged from the stream-directing mechanism or switching valve I8 through line 28, preferably to suitable recovery equipment, not illustrated. However, when desired, heat recovery means employed in either orl both streams may be located ahead of the stream-directing mechanism to reduce the temperature at which this mechanism must operate.

'I'he stream-directing mechanism I8 may be the same or of a different type than the stream directing mechanism 4 and, in the particular case here illustrated, they are shown as the same type of mechanism. Figure 4 illustrates the flow through valve I8 when regeneration is taking place in zone I4 and conversion of the reactants is taking place in zone I5. Figure 5 illustrates the ow through valve I8,when reactivation is taking place in zone I5 and conversion of the reactants is taking place in zone I4.

It wm be apparent'tnatwitatnenow' and geeral type and arrangement of apparatus indicated in the drawing, the aforementioned advantageo'us features' ofthe invention may be applied to any catalytic conversion or treating process of the general type above mentioned.

We claim as our invention:

1. A process .of catalytic conversion, which comprises initially heating a stream of reactants to be converted to a relatively mild temperature,

lthereafter passing the'initially heated stream through one of a plurality of. n uid conduits and therein heating the same lto a substantially higher temperature, at which" the desired conversion reaction will occur upon contact of said heated stream with a 'catalyst capable of pro-I moting .said reaction, thereafter passing the highly heated stream through one of a plurality of reaction zones incontact with a mass o f said catalytic material and therein eii'ectingv said con'- verslon reaction, periodically discontinuing thev iiow oli-said stream of initially heated reactants through said fluid conduit and reaction ,zones and passing the initially heated stream of reactants in series through another of said fluid con, duits and another of said reaction zones, wherein said higher heating and the conversion reaction are continued, while simultaneously passing a stream of reactivating material for said catalyst through one of saidliluid conduits previously employed for said high temperature heating of. Y

previously employed for conducting said conversion reaction, therein contacting the same with a masslof the said catalytic vmaterial disposed therein, and effecting the removal therefrom of fsaid deleterious material. Y

2. A process of catalytic conversion, which comprises initially heating afstream of reactants' to be converted to a relatively mild temperature, thereafter passing the initially heated stream through one of a plurality of fluid conduits and therein heating the same to a-substantially higher temperature, at which the desired conversion reaction will occur upon contact of said heated stream with a catalyst capable 'of pro-1A` moting said reaction,l thereafter passing the highly heated stream through one`V of a plurality of reaction zones in contactwith wa mass of said catalytic material and therein effecting said conversion reaction, periodically y.dis'eontinuirig the,

iiow of. said stream of initiallytheated reactants through said fluid conduit and reaction zones and passing the initially heated stream -of reactants in series through another of said fluid con`- duits and another of, said reaction zones, wherein said higher heating andftthe conversion reaction are continued, while simultaneously passing a stream of partially heated reactivating material for said catalyst through one of said fluid conduits previously employed for said high temperature heating of the reactants, therein further heating the reactivating `material toa temperature at which it will effect removal from the catalyst of deleterious materials deposited thereon during the conversion reaction, passing the heated stream of reactivating material through one of said reaction zones .previously employed for conducting said conversion reaction, therein contacting the `same with a mass of the said cataasians? Y lytic material disposed therein, and effecting the removal therefrom of said deleterious material. 3. A process for the catalytic conversion oi'. hydrocarbons, which comprises initially heating a stream of hydrocarbons to be converted to a relatively mild' temperature, thereafter passingA -the initially heated stream through one of a plurality of iiuid conduits and therein heating at which the desired conversion reaction will occur upon contact of said highly heated stream with a catalyst capable of promoting said reacthe same toa substantially higher temperature tion, thereafter passing the highly heated stream through one of a plurality of reaction zones in contact'with a mass of said catalytic -material` and therein enecting said conversion reaction,

' periodically discontinuing the flow of the stream of initially 'heated hydrocarbons through said `fluid conduit and reaction zone and passing the initially heated stream of hydrocarbons in series through another of said fluidy conduits andanother of. said reaction zones, wherein said higher heating and the conversion reaction are continned, while simultaneously passing a stream of oxygencontaining gases through one of said fluid cnduits previously employed for said high4 temperature heating of the hydrocarbons, therein heating the oxygen-containing gases to a temperature at which they will effect combustion of heavy carbonaceous materials deposited on the catalyst during said conversion reaction, passing the heated stream of oxygen-containing gases through oneof said reaction zones previouslyv employed for conducting saidA conversion, therein contacting the same with a mass of the said catalytic material disposed therein, and burning therefrom Asaid deposited carbonaceous material.

f 4.'A process for the catalyticcracking of hydrocarbons, which comprises initially heating a streaml of the hydrocarbonsfto be cracked to a temperature below that at which any appreciable formation and deposition of coke will occur, thereafter passing the initially heated stream 'through one of a plurality of fluid conduits and therein heating the same to a substantially higher temperature at which said cracking will occur uponcontact of the highly heated stream with a catalyst capable of promoting the crack the cracking reaction are continued, while simultaneously passing a stream of oxygen-containing gases through one of said fluid conduits pre.

viously employed for said high temperature heating of'. the hydrocarbons, therein heating the oxygen-containing gases to a temperature at which they will eiect xcombustion of heavy carbonaceous materials deposited on the catalyst' during the cracking reaction, passing the heated stream of oxygen-containing gases through one of said reaction zones previously employed for conducting the cracking'reaction, therein contacting the same with a mass of the said catalytic material disposed therein, and burning therefrom said deposited carbonaceous material.

5. A process for the catalytic dehydrogenation of hydrocarbons, ywhich comprises initially heatiii)` ings, stream o! thehydrocarbons to be dehydrogenated to a temperaturebelow that at which any appreciable formation and deposition of coke will occur, thereafter passing the initially heated stream through one of a 'plurality-ot huid conduits and therein heating the same to a substantially higher temperature at which the desired dehydrogenating reaction.will occur upon contact of the highly heated stream with a catalyst capable of promoting said reaction, thereafter passing the highly'heated stream through one of a plurality oi.' reaction zones ingcontact with a mass of said catalytic material and therein effecting said dehydrogenating reaction, periodically discontinuing the iiow ofthe stream of initially heated hydrocarbons through said fluid conduit and the reaction zone and passing the finitially heated stream in series through another f of said fluid conduits and another of said reaction zones, wherein said higher heating and the dehydrogenating reaction continue, while simultaneously passing a stream of oxygen-containing gases through one of said fluid conduits preg viously employed for said high temperature heating ofthe hydrocarbons, therein heating the oxygen-containing gases to a temperature at which they will eilect combustion of heavy carbonaceous stream of oxygen-containing gases through one of said reaction zones previouslyl employed for conducting said dehydrogenati-ng reaction, therein contacting the same with a mass of the said catalytic material disposed therein and burning therefrom said deposited carbonaceous material.

6. An apparatus of the class described comprising in combination, a primary heater, means for passing a stream of reactants'to be catalytically converted through said primary heater and discharging the heated stream of said reactants therefrom, a plurality of separate iiuid conduits each disposed in a zone of higher temperature than that of the primary heater, stream-directing means communicating with the discharge end of said primary heater and with the inlet end of each of said separate fluid conduits, an inlet conduit for a streamv of reactivating material communicating with said stream-directing means, the stream-directing means being adapted to selectively direct the stream of reactants discharged from saldprimary heater to any one of said separate iluid conduits and simultaneously direct said stream of reactivating material to another of said separate fluid conduits, a plu-` rality of reactors each containing a mass of catalytic material capable, while 'in active state, of promoting said'conversion reaction and each communicating with a separate fluid conduit of said plurality thereof and discharge conduits from each of said reactors. I

7. An apparatus of the class described comprising, inn combination, a primary heater, means for passing a stream of reactants to be catalytically converted through said primary heater and discharging the heated stream of said reactants therefrom, a plurality of separate `iluid conduits each disposed in a zone of higher temperature than that of the primary heater, stream-directing means communicating with the discharge end of said primary heater and with the inlet end of each. of said separate iiuid conduits, an inlet conduit for a stream of reactivating material communicating with said stream-directing means, the stream-directing means being adapted to selectively direct the stream of reactants discharged from `said primary heater to any one of said separate iluid conduits and simultaneously direct said stream of reactivating material to another of said separate iiuid conduits, a plurality of reactors each containing a mass of catalytic material capable, while in active state, of promoting said conversion reaction and each communicating with a separate iiuid conduit of said plurality thereof,Y

discharge conduits from each of said reactors communicating with another stream-directingY means, a discharge conduit for products 0I the y ROBERT PYZEL. l CLARENCE G. GERHom. 

